Service tax on telephone bill

Dear All,

We are a manufacturing unit and where the admin section and factory section is on the same premises. There is no clear seggregation of staffs and workers. We receive telephone bill combined, after charging service tax, can we claim input of such service tax paid, considering that it is directly related to my production?

Also company pays several mobile bills of its staff (whether directly or indirectly related to production)..shall we get credit of the sevice tax charged on the bill to us?

Similarly what about repairs and maintenace of Computers and printers?

SInce we are a manufacturing unit, generally what kind of services will qualify for us to take cenvat credit?

Thanks in advance for your kind response.